1. Field of the Invention
The invention relates to a process for finishing an end surface of a non-circular post.
2. Description of the Related Art
Referring to FIG. 1, a conventional molding core 1 for forming an optical lens piece with a non-circular cross-section includes a surface 101, four lateral sides 102 connected to the surface 101, and a peripheral edge 1011 surrounding the surface 101. A conventional process for finishing the surface 101 of the molding core 1 comprises the steps of rotating the molding core 1, and using a cutter 2 to finish the surface 101 to a predetermined precision.
Although the aforementioned process can achieve its intended purpose, it has the following disadvantages:
Referring to FIG. 2, when a circular track (P1) of the cutter 2 is within the boundary of the peripheral edge 1011 of the molding core 1, the cutter 2 cannot hit the lateral sides 102 of the molding core 1. However, when a circular track (P2) of the cutter 2 exceeds the boundary and intersects the peripheral edge 1011, two continuous portions of the circular track, arc AB and arc CD, and two non-continuous portions of the circular track, arc BC and arc DA, are formed. When the circular track (P2) is at point A or C, the cutter 2 is likely to hit the lateral side 102. When the circular track (P2) is at point B or D, the cutter 2 is likely to move swiftly away from the lateral side 102, thereby resulting in damages not only to the cutter 2, but also to the surface 101 of the molding core 1.